John 17:11

And I am no more in the world, and these are in the world. Holy Father, keep them in thy name which thou hast given me, that they may be one, even as we are.

No more in the world ... refers to the physical absence of Jesus after the resurrection and ascension. Spiritually, the Lord continues to be with his disciples (Matthew 18:20).

And these are in the world ... refers to the mortal state of the apostles who would continue to be the object of Satan's bitterest hatred and opposition. Jesus' physical departure would make them even more the object of Satan's attack and their status even more precarious. These considerations prompted the fervent prayer on their behalf.

Holy Father ... is one of three terms of address directed to God in this prayer, the others being "Father" (John 17:1,4, and John 17:11), and "O Righteous Father" (John 17:25).

Keep them in thy name ... There is no way to avoid respect of the importance attached to the sacred name of "Jesus Christ," and it is likely that here is a reference to that compound title introduced in John 17:3. Let men face it, salvation is accomplished in an all-powerful name, a fact which the apostles strongly emphasized. "Neither is there any other name under heaven, that is given among men, wherein we must be saved" (Acts 4:12). Immediately after that statement, Peter pronounced that sacred name, and, significantly, it was the compound title found in this prayer, "Jesus Christ."

That they may be one ... was a plea for unity, primarily of the apostles, but, by extension, applicable to all Christians. See under John 17:22 where this admonition is repeated.